Airships, such as blimps, dirigibles, aerostats, or any other lighter-than-air platform, including high-altitude airships, maintain a gas-impervious envelope that provides various discrete regions that separately contain air and a lifting-gas, such as helium or hydrogen. By varying the amount of air within the envelope, via a combination of electrically controlled blowers and valves, the elevation of the airship can be controlled. To navigate the airship in a desired direction or heading, a plurality of electrically powered propulsion units, such as propeller units for example, are disposed about the perimeter of the envelope. In addition to the systems used to maneuver the airship when in flight, the airship may include a gondola or other structure that contains the payload of the airship, which in addition to the various electronic navigation control systems contained therein, serves as a storage area for various electronic components that may be used while the airship is in flight. In particular, the payload may serve as a repository for various electronic devices such as research instrumentation, RF transceiving devices, analysis tools, or any other desired piece of equipment. Moreover, the role of airships continue to expand and, as such, are increasingly being used in research, entertainment and other endeavors, whereby a significant number of computers, sensors, transceivers, and other electronic components are carried aboard the airship and are in need of power supplies thereby. As such, it is evident that the requirements for electrical power aboard the airship are significant and are likely to continue to increase as the role of the airship expands beyond that of just flight.
Thus, to meet the energy demands required by the valves, blowers, and propulsion units, as well as the other electronic components maintained as part of the payload, a combination of rechargeable batteries, regenerative fuel cells and solar panels may be used as power sources aboard the airship. Thus during diurnal periods, when solar radiation from the sun is available, power aboard the airship is derived from the solar panels, which harvest the solar energy incident on the envelope of the airship. In addition to actively powering the electrical components aboard the airship, a portion of the unused solar energy is used to generate hydrogen and oxygen gasses by electrolysis of the waste water from the fuel cells or stored in rechargeable batteries that are maintained as part of the payload of the airship. During nocturnal periods, or those periods when solar energy from the sun cannot be harvested, the airship is restricted to operating on the power that it has stored in the rechargeable batteries and/or power generated by the fuel cells by the consumption of stored hydrogen and oxygen.
While the combination of the solar panels batteries and fuel cells provide an acceptable level of energy capacity, they suffer from various drawbacks. In particular, the rechargeable batteries are typically large, heavy, and consume a significant amount of the payload of the airship. For example, approximately 4,000 lbs. of batteries are typically needed to provide the power necessary to fully power the airship during its descent from altitude. In addition, the solar panels tend to be heavy and are susceptible to being easily broken or damaged. As such, the weight contributed by the batteries and solar panels currently utilized by airships negatively impacts the maneuverability of the airship, its ability to attain desired altitudes and traveling ranges, and thus serves as a significant limitation in overall performance of the airship. Furthermore, a substantial expense is also incurred to maintain, charge, and periodically replace failed batteries or fuel cells to ensure that the airship has optimal power capacity during its operation.
Therefore, there is a need for a power-generating laminate that is configured to be integrated into the envelope of an airship, which can harvest electrical power from the structural and thermal changes of the envelope associated with the operation of the airship. In addition, there is a need for a power-generating laminate that can harvest power from the structural expansion, contraction or strain otherwise imposed on the envelope of the airship during its operation. Furthermore, there is a need for a power-generating laminate that can harvest power from the thermal changes experienced by the envelope of the airship during its operation. Still yet, there is a need for a power-generating film that can generate power without occupying space within the payload of the airship. In addition, there is a need for a power-generating laminate that possesses both piezoelectric and pyroelectric properties.